Jack



Jan. 1, 1935. G, s wHlTEHEAD 1,986,129

JACK

Filed Oct. 19, 1953 ['qyeSteplw/L [Waite/lead,

is ('lttowmg Patented Jan. 1, 1935 I r l 4 UNITED ST TE ATENroEFIcE George Stephen Whitehead, St. John, New

: Brunswick, Canada Application October 19, 1933, Serial N0. 694,305.

ZCIaims. .(Cl.254"126) l This. invention relates to jacks, and itis the Figure 4 is a side elevation of one .of the conobject. of the inventionto providea jack in which nection members; I v the lifting-block may be lowered t o within a very Figurefi is a side elevation of the lifting block; short distancefromthe ground andgto provide ,Figure 6 is .a side elevation of one oflthe moreover in this type of jack, a construction trave1lers;-

which contains few parts and'will not easily get Figure 7 is a side elevation of a modified form out of order.. c ofthe lifting blockhaving a plurality of grip- In previously known jacks of'theogeneral type ping teeth on its upper face; and I according to this invention the connections -be- Figure 8 is a further modifiedfform :of the.

. tween the travellers and the lifting block have lifting block. 1 I l l been complicated andin many respects inefii- In the formshown in Figures 1 to 6 inclusive, cient. One of the main disadvantages of prior the jack vcomprises a base A including a bottom art constructions has been that the connecting portion ,1, end. portions 2, side portions 3, and members between the travellers and the lifting short top portions 4. The center of'the base is block have borneon pivots extending throughthe attachedfto-a supporting-block 5 for the rotravellers and on pivots extending through the tatable actuating member 6, the blockbeingheldlifting block, tending in this way to exert a in position on the baseIby bolts'l. :The actushearing action which increases with an inating member 6 comprises'left and right hand crease in pressure on the lifting block. This screwthreaded'portions 8 and Ba'respectively,

: action often results in parts becoming disaligned and its end is squared as at'9,:so that it may be 20;.

and in the jack becoming difficult of operation. rotated .by any suitable form of arrangement.

According to this invention-a jack 'provided Mounted ontheleft and right hand screw with a rotatable actuating member in the form threaded portions 8. and 8a 'of l the actuating of a double oppositely-screw threadedshaft and member 6; are travellers wand 11 respectively,

with travellers mounted on this shaft andladapteach formediwith an upstandinghook-like pro ed to be, moved towards each other upon its jection 12, theinterior of 3' which is shaped'to rotation in one direction, has a liftingv block and. form 'axbearing surface 13, 'as shown in Figure members extending between the travellers'and: 6.. The lifting block 14 is formed with two bearthe lifting block and bearing directly and only ing surfaces 15 facing'in opposite directions and 3 thereupon. In the form of construction shown, formed, if .desire'd,..to extend over arcs of not 11 the bearing surface on the travellers and on the x; more than.180 Extending between the travellifting blockextend over the entire Width of lers wand '11 and'the lifting block'lare memthese parts, the bearing surfaces on the travel bers 16 of channel-formation having their open lers facing. each other and those on the lifting side-downwardly dire ted; Thes embers are block being on opposite sides thereof. The .con-.- formed at one end with upstanding portions 17 351 necting members having bearing surfaces formed of cylindrical form cooperatingwith the bearing to coact with the surfaces on the travellers surfaces'1'3'of the travellers and at'their other and lifting block and are of channel formation. end with": outstanding portions 17 of cylindrical: so that in their lower position they-will partial-' form cooperating with the'bearing surfaces 1 13 1y. enclose the actuating shaft. The bearing of the travellers and at their other end with 40 surfaces on the liftineblock, m y f desired, be outstanding portions. 18' of cylindrical'for'mcomade to extend over arcs of "at the moStlSO operatingwith the bearing surfaces 15 in the so as to render the blockcapable of being dislifting block. It is to be noted that the memengaged from the connecting members by sim-*' bers 16'bear directly'and only upon the travelply being lifted up, in which case the connecting. lers and upon the lifting block and not'on pivots 45 members will drop down to such a position that" set in these latter. In this' way the undesirable their p are parallel With the base of the shearing action referred to in connection with vice." I prior art'constru'ctions isavoided. In'th'eform In the drawing: of construction shown, the channel members,"

5 Figure 1..isa partly sectional side elevation travellers and lifting block are of the same r of the device in lowered position; width, and therefore contact with each other Figure 2 is a section along the line 22 of over their entire width. This is the most na- F ure 1; tural way of making the device, but it is obvi- Figure 3 is a section along the line 33 of vous that any of these parts could be made wider Figure than the others if desired. 55

In my device, the bearing surfaces 15 on the block 14 are generally formed so as to grip the portions 18 of the member 16, that is, they'are;

-block is removed the channel'members drop down till they lie parallel with the bottom 1 of the base.

away in a very small spacej g s It will, be noted in the structureshownin laFigures land 5, the lifting block is provided, with overhanging ledge portions 14" which areadapted to overhang the bearings 15 and provide an efficient rest for bearings 15.

In Figure 7 there the lifting block upon the is shown a. iirumgmock-14a of similar construction 't'o the lifting' blockj 14,-

-- The socketsi13 in members 10and11pr'ovide' ing-niembersm16. -This feature offers'advanta'geover/pivotal bearings inhaving much's'less frictionpersquare 'inch', eliminating any directshear: and due to thexincreased area of longitudinal I bearing surfaces of pivotal connections insuresgmorefstability whenthe jack is inelevation'.,: i.

-; -variolis modifications may befimade in this invention without rdeparting from the spirit thereof ,or thews'cope of the, claims, and therefore the exact-forms 'areto be taken-"as illusi trative onlyand notin a limiting sense, andzit is desired that only such limitations, fsha'll .-be; placed jthereon' as are:,disclosed in the'prior; artx i ing sockets extending the'full width of the liftorare set forth in the accompanying claims; 1

, What "Ifclaim" as myinvention is':'- 1; Aj-j-ack comprising; an,elongated*base hav L ingside-walls and,:end walls',,-aj bearing block secured in :saidffbase midwaythe, length thereof,

an actuating? screw extending longitudinally in saidI-base'with 'its in-temiediate portion journaledqthrough said i bearing block and its endportions journaled-through the end walls ofthe threaded" portions 'ofsaid screw whereby the travelers will be moved longitudinally in the'base when thescrewis rotated, each travelerchaving In this way the device may be put lside walls'thereof', said links each having at its outer end an upwardly extending cylindrical atongue rising therefrom and curved longitudinally to overhang the traveler, said tongue corresponding in width to the traveler and extending towards the inner end of the traveler and defining a semicircular bearing socket between the tongue and upper face of the traveler, a lifting block disposed over said bearing block, and having each end recessed for its full width to form a semicircular bearing socket and an outstanding tongue along the upper portion thereof, and links extending longitudinally of said base between the lifting block and travelers and having depending side flanges extending into the base in contacting engagement with bearing extending its full width and rotatably received in the'bearing of the adjoining traveler; and. each link having at its inner end a downwardly disposed cylindrical bearing extending its full'wi'dth and rotatably received in a bearing socket at the adjoining end of saidlifting block whereby vertical'movement-will be impar't'ed to'the lifting block when the screw is rot'atedk 2. A jack comprising an elongated base having a bottom and side walls, the side walls having inwardly extending flanges along their upper edges carrying depending lips at their inner edges, a bearing block in said base secured to the bottom thereof midway its length and having its-lower portion contacting with side walls of the base and its upper portion reduced in width and extending between the depending lips, travelers-in-end portions of said base resting upon the bottom thereof and each having its lower portion contacting with side walls of the base and its upper portion reducedin width and extending between the lips, an actuating screw extending longitudinally in said base with its intermediate portion journaled through the bearing-block and its end portions journaled through the end' walls of the base, portions of the screw between the bearing block and oppo site ends of the base being oppositely threaded and engaged through thr'eaded' bores of the travelers to impart movement to the travelers in opposite directions longitudinally of the base when the screw is'rotated, a lifting block disposed over said bearing block and having its opposite ends recessedto form semicircular bearof their inner ends also formed with recesses defining'bearing sockets extending the full width of each traveler, and links extending longitudik nally of said base between the lifting" blockand travelers and along their sides being provided with. depending flanges slidably fitting against the'depending lips of side walls of the-base and snugly .fitting betweenthe lips and reduced upper portions of thetravelers and bearing'block, ends of the links being formed at their ends with cylindrical bearing-sleeves extending their fullwidths and rotatably received in the bearing sockets of the travelers and lifting block whereby vertical movement will be imparted to the lifting block when the screw is rotated.

GEORGE I STEPHEN WHITEHEADL 

